Call of Duty: Modern Warfare 2 (2009)

What you are trying to do with this achievement is to shot and kill two enemies at the same time. Your best bet is to try and be in front of a group coming downstairs and shoot at them when they are one behind the other. If that fails shoot into a crowd and it should pop up eventually. I personally got this on the "Team Player" mission when the enemies started appearing on the bridge at the start of the mission.

This is an extremely easy achievment, one of the first you will get while making progress through the campaign. Through the hordes of MW2 enemys theres bound to be a lot of situations when 2 enemies are one behind the other. Yes as "Chizzle e4" said you can shoot people head on while they are on a snowmobile in the Cliffhanger level. Notice in the achievment description it mentions you can obtain it during playing special ops. I personally have got many 2 for ones, collaterals, double kills (whatever you want to call it) on the first sniper mission in Special Ops where you are on a building with troops running towards you. Note, you can't get it with a grenade launcher, only with a gun. Guns can shred the AI to peices so if there happens to be the instance in which someone is standing behind another enemy all guns have enough damage power to penetrate through the first to kill the second (Especially LMGs).

If you didn't manage to get this randomly on campaign then the quickest possible way is to load up "Contingency" in Act III.

Roach and Price have silenced sniper rifles, about 15 seconds into the level a scout patrol passes in the distance, the soldiers are walking side by side, one pop to the head of the 1st guy in the 2nd row of the patrol and the achievement is yours.

I hadn't got it up to that point, saw the potential and it paid off. Load Last Checkpoint if you'd prefer to continue the mission stealthily.

what u need to do is the first level u play as the u.s Rangers is to use the grenade launcher thats on your machine gun (or whatever it is called ) (sorry) and fire across to were u can see your eneemies.and thats basicly how i did it